diff --git a/wp-content/themes/twentyten/attachment.php b/wp-content/themes/twentyten/attachment.php
index 22940592de..168347f0d2 100644
--- a/wp-content/themes/twentyten/attachment.php
+++ b/wp-content/themes/twentyten/attachment.php
@@ -42,13 +42,13 @@
 							);
 							if ( wp_attachment_is_image() ) {
 								echo ' <span class="meta-sep">|</span> ';
-								$size = getimagesize( wp_get_attachment_url() );
+								$metadata = wp_get_attachment_metadata();
 								printf( __( 'Full size is %s pixels', 'twentyten'),
 									sprintf( '<a href="%1$s" title="%2$s">%3$s &times; %4$s</a>',
 										wp_get_attachment_url(),
 										esc_attr( __('Link to full-size image', 'twentyten') ),
-										$size[0],
-										$size[1]
+										$metadata['width'],
+										$metadata['height']
 									)
 								);
 							}